Let’s say you’d like to soften a background, or soften certain parts of a person’s physical features. You’d use a concept called “depth of field”, where the “field” is everything your camera sees, from the closest objects to the most distant, and the “depth” is how much of that field is in focus (the close objects, the far ones, everything). This concept is something many have the habit of doing in photoshop, but it doesn’t need to be that way.

Photoshop can emulate effects that are native to the camera lens, but there are a few really excellent reasons NOT to do it this way:

1. Using your camera’s features to control depth of field will produce a much more natural effect than Photoshop.
2. You’ll save a whole lot of editing time in the long run if you invest a little time up front to learn the intricacies of your camera’s lens aperture, or “f-stop” settings.

What is Aperture / F-Stop?
At the most basic level, the aperture is the size of the “opening” through which your camera collects light, whereas f-stop is the way we measure the size of this opening.

When the aperture is open all the way, your depth of field is at its smallest. That is to say, it’s easy to create a photograph where only a small portion of your subject is in focus. When the aperture is closed all the way (well it’s never really closed all the way, just super small) your depth of field is at its largest and nearly everything can be brought into focus from the closest to the furthest.

When speaking f-stops, what looks like a relatively low number (f/2.8 for example) corresponds to a large aperture, a high number (f/22, f/64) corresponds to a very small aperture.

For more on the basics of your camera lens and aperture, see the previous post on the subject of Aperture.

Handmade Aperture in Action
Now for some hands-on exercises, literally! Here is a fun little way get a very real concept of the effect of large and small apertures… by making an aperture with your hands, you can actually see the difference in your vision:

1. Wherever you happen to be, find two objects with text or some other kind of details on them. One of these objects should be a “near” object and a one “far” object. The near object should be close enough so that, when looking at it, the far object is out of focus.
2. Line up the objects so they are both in your field of vision and take your thumbs and forefingers and smash ‘em together like so (funny face not required):



3. Squeeze tightly until there is just the smallest hole between your four fingers. You’ve just created a small aperture. With your fingers!
4. Looking through your personal small aperture, focus on the near object and slowly make the aperture larger. Notice that, as you make the aperture between your fingers larger, the background object begins to get less and less in focus. Your depth of field is getting smaller!

You can play around with this exercise a bit, but the concept you want to bring away is:

• A tiny aperture can produce a great huge depth of field.
• A large aperture (as is the case with the uninhibited human eye) can produce a very shallow depth.
• Lastly, the closer these objects are to you, the more pronounced this shallow depth of field is… once you begin to look at objects which are more than a dozen feet away, things begin to come into a general clear focus. Unless you’ve lost your contacts, and that’s a whole different problem.

Stay tuned for Part 2…

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